In an elevator system, a regenerative condition may arise between the beginning and the end of an operation when the elevator car is operated up or down. If this regenerative electrical power is not controlled, an overvoltage occurs, stopping the device, and therefore measures for controlling this regenerative electrical power are taken. One of those measures is a DBR circuit.
In this circuit, a series circuit consisting of a resistor and a switching element (for example, a transistor) is connected between the input terminals of an inverter device working as an electrical power source for driving an elevator car, and the regenerative electrical power is consumed by means of the ON/OFF control of the switching element to prevent the overvoltage.